ATOMS AND MOLECULE
Greek philosophers in the pre-Socratic era first expressed the feel that matter is not infinitely divisible, and that there exist invisibly small ultimate particles called pinchs (Greek for unsplittable)that constitute all perceptible matter. The stoical philosophers and to some degree Aristotle and his followers opposed this opinion, and the debate continue sporadically into the early modern era. The idea of atoms became increasingly popular in the seventeenth and eighteenth centuries, but natural philosophers could do little more than speculate about them.
Chemists began vicariously to search the world of ultimate particles soon after the death of Antoine-Laurent *Lavoisier in 1794. Lavoisiers definition of a chemical element - a chemically irreducible species of matter- provided for the first time a basis for an confirmable approach to atoms, for to each one element might be though to consist of a characteristic kind of irreducible particle.
If the atom of the various elements had truly distinguishable characteristics, such as weight, for example, then that fact ought to be discernible in the combinations of the various elements with each other. And so it was, for the laws of stoichiometry (regularities in the weight proportions in which elements combine with each other) were soon discovered, by Joseph Louis Proust, Jeremias Richter, and others.
These laws could only have been discerned by starting time with the assumption of atoms. An example will make this point clear. degree centigrade and atomic number 8 combine in two different ways to make carbonic oxide and carbonic acid gas. The first has 43 percent carbon and 57 percent oxygen; the act has 27 percent carbon and 73 percent oxygen by weightIf you want to get a full essay, companionship it on our website: Orderessay
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